This is the answer I was looking for. Funny, I've been a long time linux user, and never knew about these internal names.

It does seem like a slight against our Ubuntu, Debain, Mac OS, Windows et al. comrades.

Without any context, "Hurr, durr, I'm a sheep" seems rude to users and administrators of every OS distribution. With this context, it seems like maybe not a very funny addition to a long running joke.

Ok, who's the joker who went through and linked all the animal names, etc.?